johnson v4 carb differences advantages and disadvantages ???

[spybot]

what are the advantages and disadvantages of each of these carbs?
The carbs are both from V4s both have 1 5/16[SUP]th[/SUP] Venturi
Not taking into account the jet size and the choke plate which will be romved and the jetting changed.
What advantage has the new one over the older ??
The emulsion tubes are longer on the newer carb but it does not have the tubes from the mid???
Is there any specific advantage of 1 over the other ?
Part number: 319671. 1 5/16

Part number: 317470 D2. 1 5/16

 

[racerone]

Newer is usually " improved and better " I would say.

 

[spybot]

What are the 2 tubes in front of the venturi ? Are these the mid jet air feed ?

 

[jimmbo]

?“Both from V4s”? covers a lot of years and a lot of different models

 

[interalian]

No Title

Ideally, look for carbs with primer jets already fitted on top. Latest carbies had a flate plate on top so you can clean the idle passages. This replaced a version that looked like a knuckle sandwich on top, and had lots of holes filled with lead shot. These carbs had much improved midrange carburation than the older ones. You'll also see a jet up top on the front.

 

[Faztbullet]

Newer ones have the primer feature and different idle jet positions thus different idle tube cast postions and 1-5/16" flows the same CFM no matter the model/year carb.

 

[spybot]

I think i didnt make it clear.
I have the options of one of these two models#Is there any benefit of one over the other.

 

[racerone]

Newer ones are better.----Try both and test run on a dynamometer.

 

[spybot]

typo

 

[Faztbullet]

I think i didnt make it clear.....I have the options of one of these two models#Is there any benefit of one over the other.

The newer ones have the primer fitting and jetting in the bowl not the body. Performance wise no difference....

 

[spybot]

The newer ones being the D2 Carbs???

 

[interalian]

You don't want to hold out for 1-3/8" carbs like mine? Zooooooom!

 

[spybot]

Cheers Anthony but i think they will be a tad rare lol

 

[spybot]

You don't want to hold out for 1-3/8" carbs like mine? Zooooooom!

I am giving up on the 85 to 140 conversion just going to stick to a very modded 85 and hopefully get around 90 at the prop
So i have a bubble butt exhaust, baffle plate and (BRAND NEW) Filler blocks if you know any one looking to buy the set let me know.

 

[jimmbo]

To get 90hp at the prop, you are looking at about 110 - 115 at the crank. So you would still need to port the block the same as as a 115/140/112/110 engine.
The biggest diffs between the crank rated 115 and the crank rated 140/prop rated 110/112/115 are the heads and bubble back

Why don?t you just go and find a crank rated 140, or a prop rated 110/112/115? Easier and probably cheaper, and certainly less stressful

 

[spybot]

jimmbo they are rare here scotland plus i dont have the cash if there were one

 

[spybot]

To get 90hp at the prop, you are looking at about 110 - 115 at the crank. So you would still need to port the block the same as as a 115/140/112/110 engine.
The biggest diffs between the crank rated 115 and the crank rated 140/prop rated 110/112/115 are the heads and bubble back

Why don’t you just go and find a crank rated 140, or a prop rated 110/112/115? Easier and probably cheaper, and certainly less stressful

You guys must not forget. I could not purchase my 85 in Scotland i had to travel 600mile to get the 85 trying to get a 115 or bigger is like trying to win the lotto. Ther are none to be had. If they are they are not in my budget. I spent $1000 on a just running 85hp and spent $150 in fuel and van rental to get it. The UK is nothing like the states. So please no more about just picking up am cheap 115 ect ect. I hhave to use what i have

 

[Faztbullet]

Put the hi compression heads on, install the pot belly don't cut the exhaust, lose the exhaust shoe and drill the gearcase,install a jack plate to dial it in and get a performance prop and prop it to turn 6000rpm

 

[spybot]

Thanks Fazt what part is the ehaust shoe and what part of the grearcase do i drill. I have the ability to cut the ehaust rib just not do the pting

 

[spybot]

Fazt is the shoe the filler blocks ? Where on the gearcase and drill by how much and what width ?